Statistics You Need to Know About UK Drainage

Heavier downpours, paved plots, and ageing pipes mean more water where it shouldn’t be. The data below shows how surface water is now one of the biggest everyday risks for homes and buildings across the UK.

Headline Numbers

  • 6.3 million properties in England are in areas at risk from rivers, the sea or surface water. Environment Agency
  • Flood-risk properties could rise to around 8 million by mid-century. Climate Change Committee
  • In 2024, storm overflows in England recorded about 450,000 discharges, totalling 3.61 million hours. DEFRA
  • Internal sewer flooding average improved to 1.8 per 10,000 connections in 2024–25. Ofwat
  • Water leakage: around 49 litres per person per day. Discover Water

Flood Risk & Impacts

  • 3.4 million properties face surface-water exposure; 368,000 are at the highest risk. Environment Agency
  • Oct 2023–Mar 2024 was one of the wettest half-years on record. Met Office
  • About 38% of roads and 37% of rail lines are at flood risk. NAO
  • London alone has over 200,000 properties at surface-water risk. London Councils
  • Flood insurance payouts reached about £650m in 2024. ABI
  • Annual flood damage costs the UK around £2.4bn directly, or over £6bn economy-wide. EA Strategy

Sewage Spills & Sewer Flooding

  • Storm overflow counts dipped slightly in 2024, but total spill hours stayed high. DEFRA
  • Average spills per overflow remain far above the target of under 10 per year. Ofwat
  • 12% of overflows did not spill at all in 2024. DEFRA
  • Serious pollution incidents rose year-on-year. EA
  • Internal sewage flooding affected over 5,800 properties in 2023–24. Discover Water

Leakage, Consumption & Water Resources

  • Total leakage in England ~2,700 Ml/day (2023–24). Discover Water
  • Sector leakage has dropped around 9% since 2020. Ofwat
  • Per-capita consumption averages 137 litres/day. Discover Water
  • Raw water abstraction ~14,500–15,000 Ml/day. Discover Water
  • Over 1 trillion litres lost to leaks annually. Water UK

Urban Creep, Paving & SuDS

  • Non-porous surfaces increase runoff by around 50%. susdrain
  • England introduced new SuDS standards in 2025. DEFRA
  • Water companies can now adopt a wider range of SuDS systems. Water UK
  • About 42% of UK garden area is now hard-surfaced. RHS
  • A quarter of front gardens are fully paved; 4.5 million have no plants. RHS Research
  • Urban creep adds roughly 1 m² of hardstanding per property per year. susdrain
  • Between 150k and 500k homes have drainage misconnections. ConnectRight

Costs, Insurance & Home Repairs

  • Weather-related home claims reached £585–£650m in 2024. ABI
  • Escape of water causes around £1.8m in payouts daily. ABI Guide
  • Escape of water represents around 30% of home insurance claims. ABI Data
  • Drain unblocking £80–£250; CCTV survey £100–£400; relining £60–£150/m. Checkatrade
  • Collapsed drain repair £500–£4,000+. Checkatrade

What This Means for Homeowners & Specifiers

Surface water is the everyday risk now. Design for capture, conveyance, and control:

  • Capture: Use slot or channel drains at door thresholds and patios. See Aqualevel.
  • Convey: Ensure channels have correct fall, outlets and access points.
  • Control: Integrate permeable paving and SuDS features to manage runoff on site.

FAQs

What’s the biggest flood risk for most homes?

Usually surface-water runoff overwhelming thresholds and low points—especially where paving replaced planting. Environment Agency

Do level-threshold drains work?

Yes. They intercept water before it crosses the door line and can connect to SuDS or soakaways. Aqualevel

How much water is lost to leaks?

About 2,700 million litres per day in England (2023/24). Discover Water

What’s urban creep?

The gradual paving of gardens and green areas, increasing runoff and pressure on drainage. RHS

Typical drainage repair costs?

Unblocking £80–£250, CCTV survey £100–£400, relining £60–£150/m, repairs up to £4,000+. Checkatrade

Last updated November 2025. Always verify with official data sources.